For the detection of ionizing radiation, hybrid pixel detectors are currently used which utilize, for example, chips known to the professional public under the names Medipix and Timepix. These chips have a sensor layer which is sensitive to ionizing radiation applied to the read-out chip, from the side of which there are connected electrical conductors for supplying power and transmitting communication signals. Among contemporary production, detection chips utilized have a standard-size detector surface which, excluding the non-sensitive periphery, reaches a maximum of several tens of square centimeters. Detection chips with a larger detector surface are not manufactured, because with larger detector surfaces there is a much higher occurrence of errors, making such manufacture unprofitable.
Some applications of the detector's use require that the detector surface of the detector have a area of up to hundreds of square centimeters while being capable of producing data so that the displayed image is continuous, without dividing edges between the individual detection chips—segments. In certain designs, the image from the array of the detection segments are corrected using software, while in other designs detection segments are used which have no edges (edgeless). These edgeless detection segments are arranged next to each other and their operation is synchronized to produce a clear resulting image of the detected ionizing radiation.
The disadvantages of existing designs consist in the fact that the arrangement of the detection segments next to each other is problematic, because sufficient space must be provided for connecting electrical conductors to the detection segments without disrupting the continuous detection surface.
The aforementioned disadvantages are resolved in Czech patent CZ 304899 which describes an ionizing radiation detector that allows for the creation of a continuous digital image using tightly arranged individual detection segments. The segments are tightly arranged side by side on row carriers, while the row carriers are then attached to a matrix. Each detection segment is mounted in a segment holder, wherein the sensor layer and its read-out chip preferably extend beyond the row carrier on one of the longer sides of the row carrier. The output conductors of the read-out chip of the detection segment lie in a horizontal plane on the opposite side of this overlap and are attached to electrical conductors for supplying power and transmitting the communication signals which lead along the entire row of the segments. The conductors comprise a non-sensor part of the row. The overlap is also used in the construction of a detector with a square or rectangular detector surface, in which the individual row carriers are arranged parallel to each other so that the overlaps cover the non-sensor part created by the electrical conductors of the adjacent row.
The disadvantages of this design lie in the fact that the space in the non-sensor area hidden beneath the overlap is limited. Electrical conductors are led along the row carrier in this limited space, and therefore a large number of segments can not be connected in a single row to the power supply and to the readout electronics. If, regarding the power supply connection, the power supply stabilization is too remote from the detection segments, fluctuations in the supply voltage occur and the detection segments operate erroneously, since these are very sensitive electronic components which depend on a stable power supply. Also, the limited space for electrical conductors allows for a connection to the readout electronics only serially or sequentially. A serial connection leads to longer response time and to slower image acquisition from the detector. In the presented invention, these problems are resolved by limiting the number of detection segments in a single row, wherein the mentioned electronics are arranged at the end of the row. This arrangement allows for the assembly of row carriers into continuous rectangular or square surfaces, the limitation being that the electronics are located at the two sides of the perimeter of the continuous detector surface.
The issue of the limitation of the total area is removed in patent application US 2014/0307850 which describes an ionizing radiation detector with a continuous detection surface. The detector also utilizes detection segments arranged tightly side by side, which are arranged on a rectangular matrix. The matrix has notches formed around its periphery for leading electrical conductors from each individual rows of detection segments. The electric conductors are similarly led along the detection segments and are directed into the notches, in which they are drawn vertically downwards below the matrix. The use of the notches removes the maximum size limit for the continuous detection surface, because matrices can be combined next to each other without interfering with the longitudinal lines of conductors of the individual matrices. The dead spot above each notch is occupied by a detection segment whose size and shape have been designed for this purpose.
The disadvantages of the design according to this application consist in the fact that due to the lack of space for storing conductors, the detection segments can not have their own communication channel and therefore are connected serially. This limitation in connecting has a negative impact on the data collection rate from the detection segments. Moreover, it is impossible to control the thermal stability of the power source and the detection segments. When connecting detection segments to an independent power source, a temperature difference occurs between the two parts which is difficult to compensate and has a negative effect on the stability of the power supply and the operation of the detection segments. Another disadvantage is that within the continuous surface, there form areas with limited sensitivity of detection, located above the vertical lead of electrical conductors beneath the matrix. Although the application describes the possibility of overlapping these areas with a detection segment, there is still a distortion in the detection of ionizing radiation which is difficult to eliminate even with the use of complicated software. The correction of data leads to inaccuracies and slows down the operation of the detector.
The objective of the invention is to create a module for the construction of ionizing radiation detectors with a continuous detector surface. The modules should allow for the completion of the detector in the form of a row, while the total number of detection segments in a row should not be limited. Alternatively, this would allow for the assembly of a detector with an unlimited rectangular or square detection surface. The modules would allow for both serial connection of the detection segments to the readout electronics but also for a high-speed parallel connection, or a combination thereof. Another significant feature of the invention should be the integration of power supplies into the structure of the detection module and their position in close proximity to the actual detection segments. This would remove the influence of temperature differences and would secure a stable power supply for the detection segments.